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GLAH05 Product Data Dictionary

File-Level (Global) Attributes

Attribute

Example Value

featureType

timeSeries

ShortName

GLAH05

title

GLAS/ICESat L1B Global Waveform-based Range Corrections Data (HDF5)

comment

The level 1B waveform parameterization data will contain waveform-based range corrections and surface characteristics at the full 40 per second resolution. Data granules will contain approximately 23 minutes (1/4 orbit) of data.

summary

GLAH05 contains scientific investigations of surface features defined by the waveform parameterization. File contains range corrections and the parameterizations of the waveform that were used to calculate surface elevation, and other surface characteristics. The data values were used as input data values to compute parameters on GLAH06 and GLAH12-15. Each GLAH05 file was created from an equivalent GLA05 binary formatted file. The provenance metadata shows the history that created the GLA05.

Data may not be reproduced or distributed without including the CitationForExternalPublication for this product included in this Metadata. Data may not be distributed in an altered form without the written permission of the GLAS Science Team.

CitationforExternalPublication

The data used in this study were produced by the GLAS Science Team at the ICESat Science Investigator-led Processing System (I-SIPS) at NASA/GSFC. The data archive site is the NSIDC DAAC.

Digitizer turn-on delay flag; Indicates if digitizer turn-on delay is accounted for in shot time. Data value is stored in the Metadata group.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

peaktp_flg

INTEGER_1
(UNLIMITED)

time correction flag
(NOT_SET)

NOT_SET

Peak of transmit pulse flag; Indicates if time to peak of transmit pulse is accounted for in shot time

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

Group: Data_1HZ/Geolocation

This group contains geolocation-related parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

d_lat

DOUBLE
(UNLIMITED)

Spot 1 Coordinate Data, Latitude Corrected
(latitude)

degrees_north

The geodetic latitude of the first laser spot in this record, computed from the precision orbit, precision attitude, and preliminary range. The preliminary range is used with no geodetic corrections applied. The values are in degrees North.

Rel 34 GLAS Binary Data

DS_UTCTime_1

d_lon

DOUBLE
(UNLIMITED)

Spot 1 Coordinate Data, Longitude Corrected
(longitude)

degrees_east

The geodetic longitude of the first laser spot in this record, computed from the precision orbit, precision attitude, and preliminary range. The preliminary range is used with no geodetic corrections applied. The values are in east longitude.

Co-elevation (CE) is direction from vertical of the laser beam as seen by an observer located at the laser ground spot.

Rel 34 GLAS Binary Data

DS_UTCTime_1

d_beam_coelev

DOUBLE
(UNLIMITED)

Co-elevation
(NOT_SET)

degrees

The direction, eastwards from north, of the laser beam vector as seen by an observer at the laser ground spot viewing toward the spacecraft (i.e., the vector from the ground to the spacecraft). When the spacecraft is precisely at the geodetic zenith, the value will be 99999 degrees.

Rel 34 GLAS Binary Data

DS_UTCTime_1

i_N_val

INTEGER
(UNLIMITED)

Value of N
(NOT_SET)

gates

Value of N used for waveform compression for the frame. From APID19, Offset 236. The decompress time array is available on GLAH01.

Rel 34 GLAS Binary Data

DS_UTCTime_1

i_r_val

INTEGER
(UNLIMITED)

Value of r
(NOT_SET)

NOT_SET

Value of r used for waveform compression for frame. From APID19, Offset 238. Not valid if APID19 is missing. The decompress time array is available on GLAH01.

Rel 34 GLAS Binary Data

DS_UTCTime_1

i_compRatio_p

INTEGER
(UNLIMITED)

Compression Ratios
(NOT_SET)

NOT_SET

Averaging value p for frame. From APID19, Offset 232. First N downlink samples are generated by averaging p raw digitized elements and the rest of the allocated samples in the waveform by averaging q elements (see i_compRatio_q). The decompress time array is available on GLAH01.

Rel 34 GLAS Binary Data

DS_UTCTime_1

i_compRatio_q

INTEGER
(UNLIMITED)

Compression Ratios
(NOT_SET)

NOT_SET

Averaging value q for frame. From APID19, Offset 232. First N downlink samples are generated by averaging p raw digitized elements and the rest of the allocated samples in the waveform by averaging q elements. The decompress time array is available on GLAH01.

Rel 34 GLAS Binary Data

DS_UTCTime_1

Group: Data_1HZ/Quality

This group contains flags indicating the quality or suitability of elevation data.

GPS_data_missing indicates GPS data missing from portion of this record and possible degradation

flag values

flag_meanings

0, 1

no_GPS_data_outage GPS_data_missing

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_ldtide_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Load tides flag; Indicates if a correction for the dynamic effect of load tides has been applied to the range before the elevation was calculated

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_octide_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Ocean tides flag; Indicates if a correction for the dynamic effect of ocean tides has been applied to the range before the elevation was calculated

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_setide_flag

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Solid earth tides flag; Indicates if a correction for the dynamic effect of solid earth tides has been applied to the range before the elevation was calculated.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_drytrop_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Dry troposphere flag; Indicates if a correction for propagation errors due to the dry troposphere was applied to the range before the elevation was calculated.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_wettrop_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Wet troposphere flag Indicates if a correction for propagation errors due to the wet troposphere was applied to the range before the elevation was calculated.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_intbias_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Internal range bias flag; Indicates if the internal range bias was applied to the range before the elevation was calculated and if the value of d_refRng on the record has this correction applied.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

rng_plbias_flg

INTEGER_1
(UNLIMITED)

Range Correction Flag
(NOT_SET)

NOT_SET

Post-launch range bias flag; Indicates if the post-launch range bias was applied to the range before the elevation was calculated and if the value of d_refRng on the record has this correction applied.

flag values

flag_meanings

0, 1

applied not_applied

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_offnadir_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

Off-nadir angle flag; Indicates if off-nadir angle is within limits

flag values

flag_meanings

0, 1

within_limit outside_limits

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_oceansw_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

Ocean sweep flag; Indicates if an ocean sweep is within the time frame of this record

flag values

flag_meanings

0, 1

not_ocean_sweep ocean_sweep

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_pointing_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

Target of opportunity off-pointing flag; Indicates if this record is within time of target of opportunity off-pointing

flag values

flag_meanings

0, 1

not_pointing pointing

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_steering_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

Steering to reference track flag; Indicates if this record is within target of opportunity off-pointing

flag values

flag_meanings

0, 1

not_pointing pointing

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_actual_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

Actual data bits flag; Indicates if the first 3 Attitide Flags have been set based on actual data, if ignore, then IGNORE those bits.

flag values

flag_meanings

0, 1

actual ignore

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_ist_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

IST data flag; Indicates if IST data are good, missing for at least a portion of the time of this frame, noisy for at least a portion of the time of this frame or noisy and missing for at least a portion of the time of this frame

flag values

flag_meanings

0, 1, 2, 3

good missing noisy missing_noisy

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_gyro_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

GYRO data flag; Indicates if GYRO data are good, missing for at least a portion of the time of this frame, noisy for at least a portion of the time of this frame or noisy and missing for at least a portion of the time of this frame

flag values

flag_meanings

0, 1, 2, 3

good missing noisy missing_noisy

Rel 34 GLAS Binary Data

DS_UTCTime_1

att_lrs_flg

INTEGER_1
(UNLIMITED)

Attitude Flag 1
(NOT_SET)

NOT_SET

LRS Data flag; Indicates the following conditions: LRS data good, consists of star, laser and CRS; LRS data good, but no star data for at least a portion of this frame; LRS data good, but no laser data for at least a portion of this frame; LRS data good, but no CRS data for at least a portion of this frame; LRS data good, but only CRS data for at least a portion of this frame; LRS data good, but only laser data for at least a portion of this frame; LRS data good, but only star data for at least a portion of this frame; Missing LRS for at least a portion of the time of this frame

Corrections flag; Indicates if all data in frame are good with appropriate corrections applied; or if some of data are not corrected or have measurement problems

flag values

flag_meanings

0, 1

good uncorrected

Rel 34 GLAS Binary Data

DS_UTCTime_1

altfrm_data_flg

INTEGER_1
(UNLIMITED)

Altimeter Frame Quality Flag
(NOT_SET)

NOT_SET

Frame data flag; Indicates if there are at least some usable data in the frame; or if all elevations in the frame are bad due to problems with corrections

flag values

flag_meanings

0, 1

good not_good

Rel 34 GLAS Binary Data

DS_UTCTime_1

altfrm_meas_flg

INTEGER_1
(UNLIMITED)

Altimeter Frame Quality Flag
(NOT_SET)

NOT_SET

Measurements flag; Indicates if all GLAS measurements are good or if there is at least one unusable measurement in the frame

flag values

flag_meanings

0, 1

good not_good

Rel 34 GLAS Binary Data

DS_UTCTime_1

altfrm_use_flg

INTEGER_1
(UNLIMITED)

Altimeter Frame Quality Flag
(NOT_SET)

NOT_SET

Usable Measurements flag; Indicates if there is at least one usable measurement in the frame; or if all GLAS measurements are bad

flag values

flag_meanings

0, 1

usable not_usable

Rel 34 GLAS Binary Data

DS_UTCTime_1

Group: /Data_40HZ/

This group contains data with a rate of 40HZ. 40Hz data may be indexed to the 1HZ data using the i_rec_ndx parameter in each respective time group.

Dimension Scales

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

DS_UTCTime_40

DOUBLE
(UNLIMITED)

Transmit time of each shot in J2000 seconds
(time)

seconds since 2000-01-01 12:00:00 UTC

The transmit time of each shot in the 1 second frame measured as UTC seconds elapsed since Jan 1 2000 12:00:00 UTC. This time has been derived from the GPS time accounting for leap seconds.

Rel 34 GLAS Binary Data

NOT_SET

DS_PeakNumber

INTEGER
(UNLIMITED)

Peak index number
(NOT_SET)

NOT_SET

This array indicates the index of the detected waveform peak for several parameters. PeakNumber=1 indicates the detected peak closest to the ground; PeakNumber=6 indicates the peak furthest from the ground.

Constants

NOT_SET

Group: Data_40HZ/Time

This group contains the 40HZ index and time-related parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

i_rec_ndx

INTEGER
(UNLIMITED)

GLAS Record Index
(NOT_SET)

NOT_SET

Unique index that relates this record to the corresponding record(s) in each GLAS data product.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_shot_count

INTEGER
(UNLIMITED)

GLAS shot counter
(NOT_SET)

NOT_SET

Identifies each laser shot within a record index. A combination of i_rec_ndx and i_shot_count can be used to uniquely identify each GLAS laser shot.

Rel 34 GLAS Binary Data

DS_UTCTime_40

Group: Data_40HZ/Geolocation

This group contains geolocation-related parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

d_lat

DOUBLE
(UNLIMITED)

Spot Coordinate Data - Latitude (Uncorrected)
(latitude)

degrees_north

The geodetic latitude of the forty laser spots in this record, computed from the precision orbit, precision attitude, and preliminary range. The preliminary range is used with no geodetic corrections applied. The values are in degrees North.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_lon

DOUBLE
(UNLIMITED)

Spot Coordinate Data - Longitude (Uncorrected)
(longitude)

degrees_east

The geodetic longitude of the forty laser spots in this record, computed from the precision orbit, precision attitude, and preliminary range. The preliminary range is used with no geodetic corrections applied. The values are in east longitude.

Rel 34 GLAS Binary Data

DS_UTCTime_40

Group: Data_40HZ/Elevations

This group contains surface-related parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

d_refRngNs

DOUBLE
(UNLIMITED)

Reference Range
(altimeter_range)

ns

Two-way reference range in time measured from the centroid of the transmit pulse to the last received echo digitizer gate telemetered (farthest from the spacecraft).

The surface elevation with respect to ellipsoid of the forty laser spots in this record. The elevation is calculated using the preliminary range corrected to be from the Gaussian fit to the transmit, the precision orbit, and precision attitude with no geodetic corrections applied.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_centroidInstr

DOUBLE
(UNLIMITED)

Centroid retracker offset using max peak
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location of the centroid of the received echo from signal begin through signal end defined by the standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_GmCns

DOUBLE (UNLIMITED)

Transmit pulse Gaussian peak location to centroid in ns

ns

The difference in nanoseconds of the Gaussian fit to the transmit pulse and the centroid of it. This correction was applied to the range before the computation of elevation. It is an additive correction to an elevation relative to Tx centroid to make the elevation relative to the Tx Gaussian.

Rel 34 GLAS Binary Data

DS_UTCTime_40

Group: Data_40HZ/Elevation_Flags

This group contains flags indicating the quality or suitability of elevation data.

Signal for alternate; No signal detected for alternate parameters for shot (Set if a waveform was present. i.e.: not fill data--but no leading or trailing edge detected)

flag values

flag_meanings

0, 1

detected not_detected

Rel 34 GLAS Binary Data

DS_UTCTime_40

wfq2_sig_flg

INTEGER_1
(UNLIMITED)

Received Echo Quality Flag
(NOT_SET)

NOT_SET

Signal for standard signal detected for standard parameters for shot (Set if a waveform was present. i.e.: not fill data--but no leading or trailing edge detected)

flag values

flag_meanings

0, 1

detected not_detected

Rel 34 GLAS Binary Data

DS_UTCTime_40

wfq1_region_flg

INTEGER_1
(UNLIMITED)

Received Echo Quality Flag
(NOT_SET)

NOT_SET

WF Fit Alternate; 0=WF fit using all gates; 1=WF fit using selected region from signal begin minus I_OFFSETB1 to signal end plus I_OFFSETE1 for alternate parameters for shot 40 (the offsets are in anc07_0004)

flag values

flag_meanings

0, 1

all_gates region

Rel 34 GLAS Binary Data

DS_UTCTime_40

wfq2_region_flg

INTEGER_1
(UNLIMITED)

Received Echo Quality Flag
(NOT_SET)

NOT_SET

WF Fit Standard; 0=WF fit using all gates; 1=WF fit using selected region from signal begin minus I_OFFSETB2 to signal end plus I_OFFSETE2 for standard parameters for shot 40 (the offsets are in anc07_0004)

The count of the number of gates in a waveform which have an amplitude greater than or equal to i_satNdxTh (set in anc07_0004). The value 126 means 126 or more gates are above the saturation index threshold (i_satNdxth).

Standard deviation of fit of a gaussian model to the transmitted pulse.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpazimuth

DOUBLE
(UNLIMITED)

Transmit pulse azimuth
(NOT_SET)

deg

Transmit pulse azimuth. Angle eastwards from north of the major axis of the transmit pulse, as seen by the LPA. From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpeccentricity

DOUBLE
(UNLIMITED)

Transmit pulse eccentricity
(NOT_SET)

e

Transmit pulse eccentricity as measured by the LPA. From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpmajoraxis

DOUBLE
(UNLIMITED)

Transmit pulse major axis
(NOT_SET)

m

Transmit pulse major axis as measured by the LPA. From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpintensity

DOUBLE
(UNLIMITED)

Transmit pulse intensity
(NOT_SET)

counts

Transmit pulse intensity as measured by the LPA. >From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_noiseTr

DOUBLE
(UNLIMITED)

Noise estimate from the Gaussian fit to the transmitted pulse.
(NOT_SET)

Volts

noise parameter from the gaussian fit to the transmitted pulse.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_ampTr

DOUBLE
(UNLIMITED)

Amplitude estimate of the gaussian fit to the transmitted pulse.
(NOT_SET)

Volts

amplitude parameter from the gaussian fit to the transmitted pulse

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_pklocTr

DOUBLE
(UNLIMITED)

Peak location of the gaussian fit to the transmitted pulse.
(NOT_SET)

ns

peak location (ns) Parameter from the Gaussian fit to the transmitted pulse. Peak location is relative to gate 1 of the transmit pulse.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_sigmaTr

DOUBLE
(UNLIMITED)

Sigma of the Gaussian fit to the Transmitted Pulse
(NOT_SET)

ns

sigma from the gaussian fit to the transmitted pulse.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_skewTr

DOUBLE
(UNLIMITED)

Skewness of Transmitted Pulse
(NOT_SET)

NOT_SET

Skewness of transmitted pulse.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_locTr

DOUBLE
(UNLIMITED)

Centroid of transmitted pulse in time relative to gate 1 of transmit waveform.
(NOT_SET)

ns

The time from gate 1 of the transmitted pulse to the centroid of transmitted pulse calculated from the 48 gates telemetered.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpCentX

DOUBLE
(UNLIMITED)

LPA Centroid X
(NOT_SET)

arcsec

X position of the centroid of the transmit pulse in the LPA, in arcsec from the left edge of the LPA (outer edge of pixel column 0). From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpCentY

DOUBLE
(UNLIMITED)

LPA Centroid Y
(NOT_SET)

arcsec

Y position of the centroid of the transmit pulse in the LPA, in arcsec from the upper edge of the LPA (outer edge of pixel row 0). From ANC09.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_tpOrX

DOUBLE
(UNLIMITED)

Pulse Orientation
(NOT_SET)

degrees

Pulse Orientation (Angle measured counter-clockwise from LPA X-axis).

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_TxNrg

DOUBLE
(UNLIMITED)

1064 nm Laser Transmit Energy
(NOT_SET)

joules

The 1064 nm laser pulse transmitted energy in energy units, computed from the digitized outgoing pulse and the transmit gain.

Rel 34 GLAS Binary Data

DS_UTCTime_40

Group: Data_40HZ/Reflectivity

This group contains the 40HZ Reflectivity parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

d_reflctuncmxpk

DOUBLE
(UNLIMITED)

Reflectivity Not Corrected For Atmospheric Effects from max peak
(NOT_SET)

NOT_SET

Reflectivity, not corrected for atmospheric effects from max peak, is calculated as Refl = R/T, where R is the received energy from the maximum amplitude peak of the waveform after it has been scaled for range, and T is the transmitted energy. i_reflctuncmxpk has also been calibrated for gain non-linearity (only for non-saturated waveforms), ground truth calibration and boresight shift shadowing (BSS). It is not corrected for saturation effects. If the shot is saturated (satindex above 2) then to correct for saturation the reflectivity estimate needs to be multiplied by the ratio of the corrected energy to the uncorrected energy (sat corrected reflectivity = i_reflctuncmxpk * (i_RecNrgAll + i_satNrgCorr)/i_RecNrgAll)

The atmospheric corrected reflectivity may be calculated from this uncorrected reflectivity by multiplying it by d_reflCor_atm.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_reflctUncorr

DOUBLE
(UNLIMITED)

Reflectivity not corrected for Atmospheric Effects
(NOT_SET)

NOT_SET

Reflectivity, not corrected for atmospheric effects, is calculated as Refl = R/T, where R is the received energy after it has been scaled for range, and T is the transmitted energy. i_reflctUncorr has also been calibrated for gain non-linearity (only for non-saturated waveforms), ground truth calibration and boresight shift shadowing (BSS). It is not corrected for saturation effects. If the shot is saturated (satindex above 2) then to correct for saturation the reflectivity estimate needs to be multiplied by the ratio of the corrected energy to the uncorrected energy (sat corrected reflectivity = i_reflctUncorr * (i_RecNrgAll + i_satNrgCorr)/i_RecNrgAll)

The atmospheric corrected reflectivity may be calculated from this uncorrected reflectivity by multiplying it by d_reflCor_atm.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_gval_rcv

INTEGER
(UNLIMITED)

Gain value used for received pulse
(NOT_SET)

counts

Gain value used for received pulse - uncalibrated.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_sDevNsOb1

DOUBLE
(UNLIMITED)

Standard deviation of 1064 nm Background noise, (alternate)
(NOT_SET)

volts

The standard deviation of the background noise (alternate parameters).

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_sDevNsOb2

DOUBLE
(UNLIMITED)

Standard deviation of 1064 nm Background noise, (standard)
(NOT_SET)

volts

The standard deviation of the background noise (standard parameters).

Rel 34 GLAS Binary Data

DS_UTCTime_40

Group: Data_40HZ/Waveform

This group contains the 40HZ Waveform parameters.

Label

Datatype
(Dimensions)

long_name
(standard_name)

units

description

source

coordinates

d_maxRecAmp

DOUBLE
(UNLIMITED)

Max Amplitude of Received Echo
(NOT_SET)

volts

Maximum amplitude of the received echo.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_maxSmAmp

DOUBLE
(UNLIMITED)

Peak Amplitude of Smoothed Received Echo
(NOT_SET)

volts

The peak amplitude of the received echo after it has been smoothed to remove high frequency noise (see ATBD).

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_RecNrgAll

DOUBLE
(UNLIMITED)

Received Energy signal begin to signal end
(NOT_SET)

Joules

This is calculated by taking the area under the received waveform (referenced to the observed noise) from all responses between the noise crossing before the first threshold crossing and the noise crossing after the last threshold crossing. It is a rescaled value from the GLA01 parameter d_recNrgAll_EU and is not recomputed.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_RMSpulseWd

DOUBLE
(UNLIMITED)

RMS Pulse Width
(NOT_SET)

ns

The RMS width of the entire received waveform. See Eq 5 of ATBD for derivation of range.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_areaRecWF1

DOUBLE
(UNLIMITED)

Area under received echo (alternate)
(NOT_SET)

volts * ns

Area under the received echo from signal begin to signal end using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_skew1

DOUBLE
(UNLIMITED)

Skewness of Received Echo (alternate)
(NOT_SET)

NOT_SET

Skewness of the received echo from signal begin to signal end using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_kurt1

DOUBLE
(UNLIMITED)

Kurtosis of Received Echo (alternate)
(NOT_SET)

NOT_SET

Kurtosis of the received echo from signal begin to signal end using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_nPeaks1

INTEGER
(UNLIMITED)

Initial Number of Peaks in received echo (alternate)
(NOT_SET)

NOT_SET

The initial number of peaks of the received echo; determined from the smoothed waveform, using alternate parameters

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_wfFitSDev_1

DOUBLE
(UNLIMITED)

The received echo fit standard deviation (alternate)
(NOT_SET)

NOT_SET

The standard deviation of the difference between the functional fit and the received echo using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_wfnoiseOb1

DOUBLE
(UNLIMITED)

1064 nm Background noise, (alternate)
(NOT_SET)

volts

Either the background noise mean value measured by the instrument, or the background noise calculated from the received echo using alternate parameters. See flag definition for l_WFqual - a flag is set if the background noise is calculated.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_numIters1

INTEGER
(UNLIMITED)

Number of iterations performed during fit (alternate)
(NOT_SET)

NOT_SET

This parameters contains the number of iterations for both the standard fit (shot,2), and the alternate fit (shot,1). These numbers are packed into forty bytes on the product: i_numIters(1) contains: bits 0-3: number of iterations for alternate fit for shot 1, bits 4-7: number of iterations for standard fit for shot 1 i_numIters(2) contains: bits 0-3: number of iterations for alternate fit for shot 2, bits 4-7: number of iterations for standard fit for shot 2 ... i_numIters(40) contains: bits 0-3: number of iterations for alternate fit for shot 40, bits 4-7: number of iterations for standard fit for shot 40

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_areaRecWF2

DOUBLE
(UNLIMITED)

Area under received echo (standard)
(NOT_SET)

volts * ns

Area under the received echo from signal begin to signal end using standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_skew2

DOUBLE
(UNLIMITED)

Skewness
(NOT_SET)

NOT_SET

The skewness of the received echo from signal begin to signal end using standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_kurt2

DOUBLE
(UNLIMITED)

Kurtosis of the Received Echo (standard)
(NOT_SET)

NOT_SET

Kurtosis of the received echo from signal begin to signal end using standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_nPeaks2

INTEGER
(UNLIMITED)

Initial Number of Peaks in received echo (standard)
(NOT_SET)

NOT_SET

The initial number of peaks found in the received echo; determined from the smoothed waveform, using standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_wfFitSDev_2

DOUBLE
(UNLIMITED)

The received echo fit standard deviation (standard)
(NOT_SET)

volts

The standard deviation of the difference between the functional fit and the received echo using the standard parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_wfnoiseOb2

DOUBLE
(UNLIMITED)

1064 nm Background noise, (standard)
(NOT_SET)

volts

Either the background noise mean value measured by the instrument, or the background noise calculated from the received echo using standard parameters. See flag definition for l_WFqual - a flag is set if the background noise is calculated.

Rel 34 GLAS Binary Data

DS_UTCTime_40

i_numIters2

INTEGER
(UNLIMITED)

Number of iterations performed during fit (standard)
(NOT_SET)

NOT_SET

This parameter contains the number of iterations for both the standard fit (shot,2), and the alternate fit (shot,1). These numbers are packed into forty bytes on the product: i_numIters(1) contains: bits 0-3: number of iterations for alternate fit for shot 1, bits 4-7: number of iterations for standard fit for shot 1 i_numIters(2) contains: bits 0-3: number of iterations for alternate fit for shot 2, bits 4-7: number of iterations for standard fit for shot 2 ... i_numIters(40) contains: bits 0-3: number of iterations for alternate fit for shot 40, bits 4-7: number of iterations for standard fit for shot 40

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_noise1

DOUBLE
(UNLIMITED)

Noise estimate from the Gaussian fit to the received echo (alternate)
(NOT_SET)

Volts

Noise Parameter (in physical units) determined from the fit of the received echo using the alternate parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_amp1

DOUBLE
(UNLIMITED, 6)

Amplitude estimate of the Gaussian fit to the received echo (alternate)
(NOT_SET)

Volts

Amptitude Parameter (in physical units) determined from the fit of the received echo using the alternate parameterization for up to 6 peaks. nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_pkloc1

DOUBLE
(UNLIMITED, 6)

Peak Location of the Gaussian fit to the received echo (alternate)
(NOT_SET)

ns

Peak Location Parameter (in physical units) determined from the fit of the received echo using the alternate parameterization for up to 6 peaks. nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_simga1

DOUBLE
(UNLIMITED, 6)

Sigma of the Gaussian fit to the received echo (alternate)
(NOT_SET)

ns

Sigma of the Gaussian Parameter (in physical units) determined from the fit of the received echo using the alternate parameterization for up to 6 peaks. nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_centroid1

DOUBLE
(UNLIMITED)

Centroid retracker offset (alternate)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location of the centroid of the received echo from signal begin through signal end defined by the alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_minRngOff1

DOUBLE
(UNLIMITED)

Minimum Range Offset (alternate)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location on the received echo calculated as the beginning of signal (closest to the spacecraft) using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_preRngOff1

DOUBLE
(UNLIMITED)

Preliminary Uncorrected Range Offset (alternate)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location on the received echo calculated as the end of signal (farthest from the spacecraft) using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnnoiseSigmas1

DOUBLE
(UNLIMITED)

Noise Sigmas of fit parameters (alternate)
(NOT_SET)

Volts

Standard deviation of the noise fit parameter from the diagonal of the final covariance matrix using alternate parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnampSigmas1

DOUBLE
(UNLIMITED, 6)

Amplitude Sigmas of fit parameters (alternate)
(NOT_SET)

Volts

Standard deviation of the amplitude from the diagonal of the final covariance matrix using alternate parameterization. i_nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnpklocSigmas1

DOUBLE
(UNLIMITED, 6)

Peak Location Sigmas of fit parameters (alternate)
(NOT_SET)

ns

Standard deviation of the peak location from the diagonal of the final covariance matrix using alternate parameterization. i_nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnsigmaSigmas1

DOUBLE
(UNLIMITED, 6)

Gaussian sigma (width) Sigmas of fit parameters (alternate)
(NOT_SET)

ns

Standard deviation of the sigma (width) parameter from the diagonal of the final covariance matrix using alternate parameterization. i_nPeaks1 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_thRtkRngOff1

DOUBLE
(UNLIMITED)

Threshold Retracker Range Offset (alternate)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the threshold retracker location on the received echo calculated using alternate parameters.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_noise2

DOUBLE
(UNLIMITED)

Noise estimate from the Gaussian fit to the received echo (standard)
(NOT_SET)

Volts

Noise Parameter (in physical units) determined from the fit of the received echo using the standard parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_amp2

DOUBLE
(UNLIMITED, 6)

Amplitude estimate of the Gaussian fit to the received echo (standard)
(NOT_SET)

Volts

Amplititude Parameter (in physical units) determined from the fit of the received echo using the standard parameterization for up to 6 peaks. nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_pkloc2

DOUBLE
(UNLIMITED, 6)

Peak Location of the Gaussian fit to the received echo (standard)
(NOT_SET)

ns

Peak Location Parameter (in physical units) determined from the fit of the received echo using the standard parameterization for up to 6 peaks. nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_simga2

DOUBLE
(UNLIMITED, 6)

Sigma of the Gaussian fit to the received echo (standard)
(NOT_SET)

ns

Sigma of the Gaussian Parameter (in physical units) determined from the fit of the received echo using the standard parameterization for up to 6 peaks. nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid. Adding the location to d_refRng gives the two-way range in time to the center of that peak.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_centroid2

DOUBLE
(UNLIMITED)

Centroid retracker offset (standard)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location of the centroid of the received echo from signal begin through signal end defined by the standard parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_minRngOff2

DOUBLE
(UNLIMITED)

Minimum Range Offset (standard)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location on the received echo calculated as the beginning of signal (closest to the spacecraft) closest to the spacecraft using standard parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_preRngOff2

DOUBLE
(UNLIMITED)

Preliminary Uncorrected Range Offset (standard)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the location on the received echo calculated as the end of signal (farthest from the spacecraft) using standard parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnnoiseSigmas2

DOUBLE
(UNLIMITED)

Noise Sigmas of fit parameters (standard)
(NOT_SET)

Volts

Standard deviation of the noise fit parameter from the diagonal of the final covariance matrix using standard parameterization.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnampSigmas2

DOUBLE
(UNLIMITED, 6)

Amplitude Sigmas of fit parameters (standard)
(NOT_SET)

Volts

Standard deviation of the amplitude parameter from the diagonal of the final covariance matrix using standard parameterization. i_nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnpklocSigmas2

DOUBLE
(UNLIMITED, 6)

Peak Location Sigmas of fit parameters (standard)
(NOT_SET)

ns

Standard deviation of the peak location parameter from the diagonal of the final covariance matrix using standard parameterization. i_nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_solnsigmaSigmas2

DOUBLE
(UNLIMITED, 6)

Gaussian sigma (width) Sigmas of fit parameters (standard)
(NOT_SET)

ns

Standard deviation of the sigma (width) parameter from the diagonal of the final covariance matrix using standard parameterization. i_nPeaks2 indicates the number of peaks computed. The first element corresponds to the closest-to-the-ground or 1st peak. The second element corresponds to the next-to-last (2nd) peak. The last element corresponds to the closest-to-the-satellite peak. If there are fewer than six peaks, the unused parameters are set to invalid.

Rel 34 GLAS Binary Data

DS_UTCTime_40

d_thRtkRngOff2

DOUBLE
(UNLIMITED)

Threshold Retracker Range Offset (standard)
(NOT_SET)

ns

Offset to be added to d_refRng to give the two-way range in time to the threshold retracker location on the received echo using standard parameters.

/METADATA

/METADATA

This group contains structured, computer-parseable ECHO-style collection and inventory-level metadata.

HDFVersion

HDF5 1.8.9

ControlFile

cf_name=CTL00_000_20140818_2614265_01_gla05_h5_convert.ctl

/METADATA/COLLECTIONMETADATA

Attribute

Example Value

DLLName

libDsESDTGlGLASPoly.001Sh.so

GranuleTimeDuration

1620

SpatialSearchType

Orbit

DataFileFormat

HDF5

ScienceMimeType

application/x-hdfeos

BrowseMimeType

application/x-hdfeos

BrowseOnlineMimeType

image/jpeg

ShortName

GLAH05

LongName

GLAS/ICESat L1B Global Waveform-based Range Corrections Data (HDF5)

CollectionDescription

The level 1B waveform parameterization data will contain waveform-based range corrections and surface characteristics at the full 40 per second resolution. Data granules will contain approximately 23 minutes (1/4 orbit) of data.

VersionID

34

CitationforExternalPublication

The data used in this study were produced by the GLAS Science Team at the ICESat Science Investigator-led Processing System (I-SIPS) at NASA/GSFC. The data archive site is the NSIDC DAAC.

CollectionState

In Work

MaintenanceandUpdateFrequency

Daily

AccessConstraints

Data may not be reproduced or distributed without including the CitationForExternalPublication for this product included in this Metadata. Data may not be distributed in an altered form without the written permission of the GLAS Science Team.

TemporalKeyword

Day

SpatialKeyword

Global

/METADATA/COLLECTIONMETADATA/AdditionalAttributes

Attribute

Example Value

Track

AdditionalAttributesContainer

Track_Segment

AdditionalAttributesContainer

Instrument_State

AdditionalAttributesContainer

ReferenceOrbit

AdditionalAttributesContainer

SP_ICE_PATH_NO

AdditionalAttributesContainer

SP_ICE_GLAS_StartBlock

AdditionalAttributesContainer

SP_ICE_GLAS_EndBlock

AdditionalAttributesContainer

Cycle

AdditionalAttributesContainer

Instance

AdditionalAttributesContainer

Instrument_State_Date

AdditionalAttributesContainer

Instrument_State_Time

AdditionalAttributesContainer

Timing_Drift

AdditionalAttributesContainer

Timing_Drift_Date

AdditionalAttributesContainer

Timing_Drift_Time

AdditionalAttributesContainer

identifier_product_doi

AdditionalAttributesContainer

identifier_file_uuid

AdditionalAttributesContainer

identifier_product_doi_authority

AdditionalAttributesContainer

/METADATA/COLLECTIONMETADATA/AdditionalAttributes/Cycle

Attribute

Example Value

AdditionalAttributeDatatype

int

AdditionalAttributeDescription

A count of the number of exact repeats of this reference orbit.

AdditionalAttributeName

Cycle

ParameterUnitsofMeasurement

counts

ParameterRangeBegin

0

ParameterRangeEnd

250

/METADATA/COLLECTIONMETADATA/AdditionalAttributes/Instance

Attribute

Example Value

AdditionalAttributeDatatype

int

AdditionalAttributeDescription

The number of times that we have returned to a specific reference orbit.

AdditionalAttributeName

Instance

ParameterUnitsofMeasurement

counts

ParameterRangeBegin

1

ParameterRangeEnd

99

/METADATA/COLLECTIONMETADATA/AdditionalAttributes/Instrument_State

Attribute

Example Value

AdditionalAttributeDatatype

int

AdditionalAttributeDescription

Flag word that indicates which redundant units (laser, detector, oscillator) of the GLAS instrument are in operation.

/METADATA/COLLECTIONMETADATA/CollectionAssociation/GLAH12

Attribute

Example Value

CollectionType

Dependent

CollectionUse

Level 2 file containing: corrected ice sheet elevations above the reference ellipsoid, surface roughness, reflectance, and the corrections that were used. The product parameters are the result of product-specialized waveform fitting.

/METADATA/COLLECTIONMETADATA/CollectionAssociation/GLAH14

Attribute

Example Value

CollectionType

Dependent

CollectionUse

Level 2 file containing: corrected surface elevations above the reference ellipsoid, surface roughness, reflectance, and the corrections that were used. The product parameters are the result of product-specialized waveform fitting.

ShortName

GLAH14

VersionID

34

/METADATA/COLLECTIONMETADATA/CollectionAssociation/GLAH15

Attribute

Example Value

CollectionType

Dependent

CollectionUse

Level 2 file containing: corrected Ocean elevations above the reference ellipsoid, surface roughness, reflectance, and the corrections that were used. The product parameters are the result of product-specialized waveform fitting.

/METADATA/COLLECTIONMETADATA/DisciplineTopicParameters/Land_Surface

/METADATA/COLLECTIONMETADATA/ECSCollection

Attribute

Example Value

RevisionDate

2013-11-07

SuggestedUsage

GLAH05 contains scientific investigations of surface features defined by the waveform parameterization. File contains range corrections and the parameterizations of the waveform that were used to calculate surface elevation, and other surface characteristics. The data values were used as input data values to compute parameters on GLAH06 and GLAH12-15. Each GLAH05 file was created from an equivalent GLA05 binary formatted file. The provenance metadata shows the history that created the GLA05.

ProcessingCenter

GSFC I-SIPS

ArchiveCenter

NSIDC

VersionDescription

GLASHDF V2.0-Elevations for all products except GLAH14 are now based on the range from the Gaussian fit to the transmit pulse to the Gaussian fit to the received echo. Range used for trop corrections was changed from threshold to centroid.(See Rel Notes)